JP5728967B2 - Silk screen ink composition - Google Patents

Description

  The present invention relates to a silk screen ink composition having good adhesion to a polyolefin substrate and excellent in gloss and friction resistance of printed matter.

Ink with a binder resin such as vinyl chloride / acrylic / polyester resin as a silk screen ink for film bases has been known in the past, but when screen printing is performed on polyolefin base materials using this kind of ink The adhesiveness as a printed matter is inferior, and there is a problem that the gloss is lowered, and it is difficult to obtain a stable product practically.
Therefore, there has been a demand for a silk screen ink that has good adhesion, high gloss, and excellent friction resistance.

JP 2006-82255 A

When the conventional silk screen ink was screen-printed on an untreated polyolefin base material (PP, PE), the adhesiveness as a printed matter was inferior, and there were problems in gloss and friction resistance.

In addition, conventional silk screen inks have improved adhesion to polyolefin substrates with polyolefin resins (chlorinated PP, chlorinated PE, EVA, etc.). There were problems in compatibility when two or more binder resins were used, versatility of adhesion to various printing substrates, and ink aging stability.
For this reason, the gloss, friction resistance, oil resistance (animal and vegetable oil), etc. of printed matter were inferior, and there were practical problems.
The present invention has been made in view of such conventional circumstances, and its main purpose is to have a stable adhesiveness to a polyolefin base material, particularly an untreated polyolefin film, and to be excellent in high gloss. Another object of the present invention is to provide a silk screen ink that exhibits high friction and oil resistance.

  In order to achieve the above object, the inventor of the present application has made extensive studies focusing on cyclized rubber, and found that it is extremely effective for the above-mentioned problems by using a certain chlorinated PP resin in combination. The present invention has been completed.

That is, the first invention of the present invention relates to a silk screen ink for a polyolefin substrate containing a binder resin, a solvent and a pigment.
However, (1) and (2).
(1) The binder resin contains cyclized rubber and chlorinated polyolefin.
(2) The solvent is an aromatic solvent having a boiling point of 150 ° C. or higher.

Furthermore, in the second invention of the present invention, the solvent is an aromatic solvent,
A mixture in which the cyclized rubber, the chlorinated polyolefin, and the aromatic solvent were mixed at a weight ratio of 1: 1: 2 was heated and stirred at 60 ° C. for 1 hour, and after dissolution, 3 ° C. at 25 ° C. If left unattended for days,
2. The polyolefin-based silk screen ink according to claim 1, wherein the mixture has no precipitation of binder resin and maintains solubility.

In the third invention of the present invention, the cyclized rubber and the chlorinated polyolefin are
Weight ratio 50/50 to 90/10
The present invention relates to a silk screen ink for polyolefin substrates according to claim 1 or 2.

Furthermore, the fourth invention of the present invention is the above silk screen ink for polyolefin substrate,
The substrate to be printed
A polyolefin substrate,
The polyolefin substrate is
Polyethylene substrate or
The present invention relates to the above-described silk screen ink for polyolefin substrates, which is a polypropylene substrate.

  As described above, the silk screen ink according to the present invention can exhibit excellent adhesion and gloss to a polyolefin base material, particularly an untreated polyolefin film.

  Further, by using a silk screen ink according to the present invention to print and process a transparent or translucent film or sheet such as polyethylene or polypropylene, a clear file for documents, plastic corrugated cardboard, a one-way container can be obtained. It is done.

  The screen printing ink of the present invention simultaneously uses cyclized rubber and chlorinated polyolefin as binder resins. The cyclized rubber used in the present invention can be obtained by acid-treating natural or synthetic rubber. The cyclized rubber that can be used in the present invention can be obtained by various methods. For example, concentrated sulfuric acid, organic sulfonic acids such as p-toluenesulfonic acid, chlorosulfonic acid, etc. are allowed to act directly on the raw rubber or on a rubber solution, so that a part of chain molecules in the rubber molecule is circulated. To reduce the double bond. Various types of chemical structures of the cyclized rubber have been proposed, but the cyclized rubber in the present invention is not limited to any one of them. The weight average molecular weight (measured by GPC, converted to standard polystyrene, the same shall apply hereinafter) of the cyclized rubber used is preferably 5,000 to 50,000, and more preferably 8,000 to 30,000. If the weight average molecular weight of the cyclized rubber is 5,000 or less, it is difficult to obtain sufficient film strength, and the friction resistance and oil resistance are lowered. When the weight average molecular weight exceeds 50,000, solubility in a solvent and compatibility with other resins are deteriorated. The softening point of the cyclized rubber used is preferably 80 to 150 ° C, more preferably 100 to 130 ° C. When the softening point is lower than 80 ° C., it is difficult to obtain a sufficient film strength. When the softening point is higher than 150 ° C., solubility in a solvent and compatibility with other resins are deteriorated.

  The amount of cyclized rubber used in the printing ink is 10 to 80% by weight. Preferably it is 30 to 60% by weight. If the cyclized rubber is less than 10% by weight, poor adhesion to the raw material is caused, and if it is more than 80% by weight, the ink state is poor.

  The chlorinated polyolefin used as the binder resin in the present invention preferably has a chlorine content in the range of 5 to 60% by mass, more preferably in the range of 10 to 50% by mass. If the chlorine content is less than 5% by mass, the solubility in solvents and compatibility with other resins are poor, and if the chlorine content exceeds 60% by mass, sufficient adhesion to polypropylene films, etc. when inked. Cannot be obtained. The molecular weight of the chlorinated polyolefin is not particularly limited, but a weight average molecular weight of usually 7,000 to 200,000 can be used, and a weight average molecular weight of 20,000 to 110,000 is particularly preferable. If the weight average molecular weight is less than 7,000, sufficient adhesion to a polyolefin substrate cannot be obtained when ink is formed. When the weight average molecular weight exceeds 200,000, solubility in a solvent and compatibility with other resins are deteriorated.

  The amount of chlorinated polyolefin used in the printing ink is preferably 5 to 60% by weight. More preferably, it is 10 to 30% by weight. When the chlorinated polyolefin is less than 5% by weight, the film strength is inferior, and when it is more than 60% by weight, the gloss is lowered and the ink state is poor.

  The weight ratio between the cyclized rubber and the chlorinated polyolefin is preferably 50/50 to 90/10. More preferably, it is 60 / 40-80 / 20. If the ratio of the cyclized rubber is lower than the 50/50 mixing ratio of the cyclized rubber and the chlorinated polyolefin, the gloss of the film is deteriorated and the ink state is poor, and if the ratio of the cyclized rubber is higher than 90/10, the friction resistance is increased. And oil resistance decreases.

  In the present invention, in addition to cyclized rubber, chlorinated polyolefin, ethylene vinyl acetate copolymer resin, polyurethane urea resin, cellulose acetate alkylate resin, acrylic resin, maleic acid resin, polyvinyl butyral, rosin resin as binder resin A chlorinated olefin resin, a fiber-based resin, or the like can be used in combination. In particular, when an ethylene vinyl acetate copolymer resin is used in combination, adhesion to a polyethylene substrate and flexibility are imparted.

  As the solvent used in the screen ink of the present invention, a solvent that dissolves the binder resin well is required, for example, glycol ether solvent, ester solvent, ketone solvent, aliphatic solvent, aromatic solvent, alcohol solvent. A solvent and an ether solvent are mentioned, If necessary, these two or more types can be mixed and used. Examples of glycol ether solvents include methyl isobutyl carbinol, ethylene glycol dibutyl ether, ethylene glycol monophenyl ether, ethylene glycol monobutyl ether, ethylene glycol monohexyl ether, ethylene glycol monomethoxymethyl ether, diethylene glycol ethyl methyl ether, diethylene glycol diethyl ether, Diethylene glycol dimethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, diethylene glycol monomethyl ether, dipropylene glycol monoethyl ether, dipropylene glycol monobutyl ether, dipropylene glycol monomethyl ether, triethylene glycol dimethyl ether Triethylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol monobutyl ether, propylene glycol monomethyl ether, 3-methyl-3-methoxy-1-butanol, ethylene glycol diethyl ether, ethylene glycol diglycidyl ether, ethylene glycol monoisopropyl ether , Ethylene glycol monoethyl ether, ethylene glycol monomethyl ether, dipropylene glycol monopropyl ether, and the like.

  Examples of the ester solvent include ethyl formate, propyl formate, butyl formate, isobutyl formate, pentyl formate, methyl acetate, ethyl acetate, n-propyl acetate, isopropyl acetate, n-butyl acetate, isobutyl acetate, sec-butyl acetate. (Iso) amyl acetate, cyclohexyl acetate, ethyl lactate, 3-methoxybutyl acetate, sec-hexyl acetate, 2-ethylbutyl acetate, 2-ethylhexyl acetate, benzyl acetate, methyl propionate, ethyl propionate, butyl propionate, propion Examples include ketones such as acetone, methyl ethyl ketone, methyl propyl ketone, diethyl ketone, methyl n-butyl ketone, methyl isobutyl ketone, dipropyl ketone, and diisobutyl. Ton, methyl amyl ketone, acetonyl acetone, isophorone, cyclohexanone, and methyl cyclohexanone.

  Examples of the aliphatic solvent include a normal paraffin solvent, an isoparaffin solvent, a cycloparaffin solvent, and the like, for example, n-hexane, n-heptane, n-octane, and n-nonane. , N-decane, n-dodecane, No. 0 solvent L, M, H (manufactured by Nippon Oil Corporation), normal paraffin SL, L, M (manufactured by Nippon Oil Corporation), etc., Isohexane, 2,2,3-trimethylpentane, isooctane, 2,2,5-trimethylhexane, Isosol 200, 300, 400 (manufactured by Nippon Oil Corporation), Supersol FP2, 25, 30, 38 (Idemitsu Kosan Co., Ltd.) Are available as cycloparaffinic solvents such as cyclopentane, methylcyclopentane, Hexane, methylcyclohexane, ethylcyclohexane, Naphtesol 160,200,220 (Nippon Oil Co., Ltd.), AF Solvent No. 4, No. 5, No. 6, No. 7 (manufactured by Nippon Oil Co., Ltd.).

  As an aromatic solvent, for example, toluene, xylene, ethylbenzene, naphthalene, tetralin, solvent naphtha, and as an aromatic solvent, swazol (manufactured by Cosmo Oil Co., Ltd., Maruzen Petrochemical Co., Ltd.) Solvesso (manufactured by ExxonMobil Co., Ltd.) ), Cactus Fine (manufactured by Japan Energy), and the like.

  Examples of the alcohol solvent include methanol, ethanol, n-propyl alcohol, isopropyl alcohol, n-butyl alcohol, isobutyl alcohol, sec-butyl alcohol, t-butyl alcohol, n-amyl alcohol, sec-amyl alcohol, 1- Ethyl-1-propanol, 2-methyl-1-butanol, isoamyl alcohol, t-amyl alcohol, sec-isoamyl alcohol, neoamyl alcohol, hexyl alcohol, 2-methyl-1-pentanol, 4-methyl-2-pen Tanol, heptyl alcohol, octyl alcohol, 2-ethylhexyl alcohol, nonyl alcohol, decyl alcohol, undecyl alcohol, lauryl alcohol, benzyl alcohol, α-terpineol Cyclohexanol, 3-methoxybutanol, and diacetone alcohol.

  Examples of ether solvents include cyclic ethers such as tetrahydrofuran and 1,3-dioxolane. Other liquid media include dimethyl carbonate, ethyl methyl carbonate, and di-n-butyl carbonate.

  In addition to the solubility of the binder resin, it is necessary to consider the viscosity of the ink, the evaporation rate (boiling point) of the solvent, etc. in addition to the solubility of the binder resin. For example, if a solvent with a low boiling point is used, In some cases, the ink viscosity increases with the passage of time during the printing operation, and the printing plate is clogged.

  In the present invention, an aromatic solvent is preferably used as the solvent, and an aromatic solvent having a boiling point of 150 ° C. or higher is more preferable. As aromatic solvents having a boiling point of 150 ° C. or higher, SWAZOL 1000, 1500, 1800 (manufactured by Cosmo Oil, Maruzen Petrochemical), Solvesso 100, 150, 200 (manufactured by ExxonMobil) Cactus Fine SF01, 02 ( Japan Energy Co., Ltd.). When an aromatic solvent having a boiling point of 150 ° C. or higher is used, a printed matter having particularly good resin solubility and printability and excellent surface condition can be obtained. In addition, since the flash point is high, there is an advantage of high safety in handling. In the present invention, an aromatic solvent having a boiling point of 150 ° C. or higher alone or a solvent having a high compatibility with an aromatic solvent having a boiling point of 150 ° C. or higher is soluble in cyclized rubber and chlorinated polyolefin. Can be used in combination. For example, ketone solvents such as methyl isobutyl ketone and cyclohexanone, and glycol ethers such as propylene glycol methyl ether and propylene glycol methyl ether acetate can be used.

  Regarding the cyclized rubber and chlorinated polyolefin used in the present invention, the solubility in the solvent used in the ink and the compatibility of the cyclized rubber and the chlorinated polyolefin in the ink film are particularly important. In the process of forming an ink film through printing, if the solubility of both resin and solvent and the compatibility of both resins decrease, the surface state of the ink film, the strength of the film will decrease, and the wear resistance, oil resistance, etc. will decrease. .

  As the cyclized rubber and chlorinated polyolefin used in the present invention, a mixture in which the cyclized rubber, chlorinated polyolefin, and aromatic solvent used are 1: 1: 2 by weight is stirred at 60 ° C. for 1 hour. Then, when the mixture was allowed to stand at 25 ° C. for 3 days, it was found that the dissolved material exhibited particularly excellent film properties. In the solubility test, the mixing ratio of the cyclized rubber and the chlorinated polyolefin is not limited to 1: 1, but is effective as one standard. Regarding the temperature, 60 ° C. is one measure for accelerating the dissolution of the cyclized rubber and chlorinated polyolefin and suppressing the volatilization of the solvent. By standing at 25 ° C. for 3 days, a resin having excellent solubility and compatibility can be selected. When used in ink, there is no separation or precipitation, and the ink has excellent wear resistance, oil resistance, etc. It was found that

  The cyclized rubber and chlorinated polyolefin satisfying these solubility are mixed in a fine state in the ink film to form a more uniform ink film, and thus exhibit excellent wear resistance, oil resistance, etc. Estimated.

  In the silk screen ink of the present invention, additives such as a leveling agent, an antifoaming agent, an anti-settling agent, a viscosity adjusting agent, a gloss adjusting agent, and a friction resistance reinforcing agent can be used as necessary. An example of the leveling agent is silicon. The content of the additive is desirably 5% or less of the total amount of the ink.

  The viscosity of the silk screen ink according to the present invention is preferably 10 to 1000 dPa · S (measured at a rotational speed of 12 rpm by an E-type rotational viscometer at a measurement temperature of 25 degrees). If it is lower than 10 dPa · S, a defect of blurring may occur if it is higher than 10000 dPa · S.

  Examples of the polyolefin substrate to which the silk screen ink of the present invention can be applied include a polyolefin film, a polyolefin sheet, and a molded polyolefin product. As the polyolefin, for example, polyethylene, polypropylene and the like can be suitably used. The silk screen ink of the present invention is characterized in that it exhibits excellent adhesion regardless of whether the surface of the polyolefin substrate is treated or not. As the surface-treated polyolefin base material, those treated by a known method such as corona treatment, plasma treatment, or flame treatment can be applied.

  As the pigment used in the present invention, inorganic pigments, organic pigments or extender pigments that can be generally used in printing inks and paints can be used. Examples of inorganic pigments include colored pigments such as titanium oxide, bengara, bitumen, ultramarine, carbon black, graphite, and extender pigments such as calcium carbonate, kaolin, clay, barium sulfate, aluminum hydroxide, and talc. Examples of organic pigments include soluble azo pigments, insoluble azo pigments, azo chelate pigments, condensed azo pigments, copper phthalocyanine pigments, and condensed polycyclic pigments.

EXAMPLES Hereinafter, although this invention is demonstrated concretely as an Example, this invention is not limited at all by the following Examples. In the present invention, unless otherwise specified, parts indicate parts by weight, and% indicates% by weight.
In the present invention, the weight average molecular weight was measured by gel permeation chromatography (HLC-8020, hereinafter referred to as GPC) manufactured by Tosoh Corporation. A calibration curve was prepared with a standard polystyrene sample. Tetrahydrofuran was used as the eluent, and three TSKgel SuperHM-M (manufactured by Tosoh Corporation) were used as the column. The measurement was performed at a flow rate of 0.6 ml / min, an injection volume of 10 μl, and a column temperature of 40 ° C.

[Example 1]
Indigo pigment (LIONOL BLUE FG-7330 (P: B 15: 3), 7 parts by weight manufactured by Toyo Ink Manufacturing Co., Ltd., cyclized rubber (1) (Alpex CK514, Nippon Cytec Industries, weight average) Molecular weight 8000, softening point 118 ° C.) 35 parts by weight, chlorinated polypropylene (1) (Toyobo Harden 523P, weight average molecular weight, 90,000-110,000, chlorine content 23%) 15 parts by weight, and solvent ( 1): A mixture of 43 parts by weight (manufactured by Maruzen Petrochemical C9 aromatic hydrocarbon swazole 1000, boiling point 150 ° C. or higher) and 0.1 part by weight of Shin-Etsu Silicon KF-96-1000CS as a leveling agent is converted into an ink by a three-roll mill machine dispersion. Ink A was obtained.
Solid content: 57%, viscosity: 90 dPa · S / 25 ° C

  Next, a surface-treated transparent polypropylene sheet (Idemitsu Pure Array) was screen-printed with a 270 mesh nylon plate as a polyolefin substrate.

  The obtained printed matter had high gloss, good adhesion to the substrate, and was free from burrs, scrapes and pinholes on the printed surface.

[Examples 2 to 11, 14, and 15, Reference Examples 12 and 13, and Comparative Examples 1 to 4]
A silk screen ink (inks B to S) was produced in the same manner as in Example 1 according to the formulation shown in Table 1, and screen printing was performed on the same substrate as in Example 1. The raw materials used in Examples 2 to 11, 14, and 15, Reference Examples 12 and 13, and Comparative Examples 1 to 4 are as follows.

Cyclized rubber (2): (Nippon Cytec Industries' Alpex CK450, weight average molecular weight 23,000, softening point 130 ° C)
Chlorinated polypropylene (2): (Nippon Paper Chemical Super Clone 814H, weight average molecular weight 20,000, chlorine content 41%)
Chlorinated polypropylene (3): (Hardlen 526P manufactured by Toyobo Co., Ltd., weight average molecular weight, 90,000-110,000, chlorine content 26%)
Chlorinated polypropylene (4): (Nippon Paper Chemical Super Clon 803M, weight average molecular weight 200,000-250,000, chlorine content 30%)
Vinyl chloride / vinyl chloride: (Solvine C, manufactured by Nissin Chemical, weight average molecular weight 31,000, PVC / vinyl acetate ratio = 87/13)
Solvent (2): Toluene (boiling point 110 ° C.)
Solvent (3): Xylene (boiling point 140 ° C.)
Solvent (4): Solvesso 150 (C10 aromatic hydrocarbon, manufactured by ExxonMobil, boiling point of 180 ° C. or higher)
Solvent (5): Cactus Fine SF-01 (Japan Energy's C9-11 aromatic hydrocarbon, boiling point 170 ° C. or higher)
In addition, the same thing as Example 1 was used for the indigo pigment, the leveling agent, and the polyolefin base material.

  As an evaluation method, the following evaluation was performed, and evaluation was performed according to each evaluation standard.

<Compatibility>
10 parts of cyclized rubber and 10 parts of chlorinated polyolefin were mixed with Swazol 1000 (manufactured by Maruzen Petroleum Co., Ltd.) and 20 parts (solid content 50%), and heated and stirred at 60 ° C. for 1 hour. Thereafter, the mixture was allowed to stand at room temperature for 3 days to determine the presence or absence of separation.
The evaluation criteria are as follows.
○: No separation △: Slight separation ×: Separation

<Adhesiveness>
After applying a cellophane tape (manufactured by Nichiban Co., Ltd.) to the printed material, it was peeled off and checked for the presence or absence of peeling.
The evaluation criteria are as follows.
○: No peeling △: Slight peeling ×: Peeling

<Glossy>
The gloss of the printed material was visually judged.
The evaluation criteria are as follows.
○: Very good (Gloss value of 70 or higher with 60 ° gloss meter)
Δ: Good (gloss value of 30 to 70 with 60 ° gloss meter)
×: Poor (60 ° gloss meter with gloss value less than 30)

<Abrasion resistance>
It was tested with a Gakushin type anti-friction tester (load 500 g, number of times 100 times vs. fine paper) to determine whether the ink film was removed.
The evaluation criteria are as follows.
○: Not taken △: Slightly taken ×: Taken

<Oil resistance>
The printed material was rubbed 100 times with absorbent cotton impregnated with salad oil to determine whether the ink film was removed.
The evaluation criteria are as follows.
○: Not taken △: Slightly taken ×: Taken

Claims (4)

Silk screen ink for polyolefin base material containing binder resin, solvent and pigment.
However, (1) and (2).
(1) The binder resin contains cyclized rubber and chlorinated polyolefin.
(2) The solvent is an aromatic solvent having a boiling point of 150 ° C. or higher. The solvent is an aromatic solvent,
A mixture in which the cyclized rubber, the chlorinated polyolefin, and the aromatic solvent were mixed at a weight ratio of 1: 1: 2 was heated and stirred at 60 ° C. for 1 hour, and after dissolution, 3 ° C. at 25 ° C. If left unattended for days,
2. The silk screen ink for polyolefin substrates according to claim 1, wherein the mixture has no precipitation of binder resin and maintains solubility. Cyclized rubber and chlorinated polyolefin
Weight ratio 50/50 to 90/10
The silk screen ink for polyolefin substrates according to claim 1 or 2, wherein In the silk screen ink for polyolefin base materials given in any 1 paragraph of Claims 1-3,
The substrate to be printed
A polyolefin substrate,
The polyolefin substrate is
Polyethylene substrate or
It is a polypropylene base material, The silk screen ink for polyolefin base materials of any one of Claims 1-3 characterized by the above-mentioned.